134 lines
3.7 KiB
Text
134 lines
3.7 KiB
Text
###########################################################################
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# simulation of a faraway orbital target (needs handover to spacecraft-specific
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# code for close range)
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# Thorsten Renk 2016
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###########################################################################
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var orbitalTarget = {
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new: func(altitude, inclination, node_longitude, anomaly) {
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var t = { parents: [orbitalTarget] };
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t.altitude = altitude;
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t.radius = 20908323.0 * 0.3048 + t.altitude;
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t.GM = 398759391386476.0;
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#t.GM = 398600441800000.0;
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t.period = 2.0 * math.pi * math.sqrt(math.pow(t.radius, 3.0)/ t.GM);
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t.inclination = inclination;
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t.inc_rad = t.inclination * math.pi/180.0;
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t.l_vec = [math.sin(t.inc_rad), 0.0, math.cos(t.inc_rad)];
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t.node_longitude = node_longitude;
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t.nl_rad = t.node_longitude * math.pi/180.0;
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var l_tmp = t.l_vec[0];
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t.l_vec[0] = -math.sin(t.nl_rad) * l_tmp;
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t.l_vec[1] = math.cos(t.nl_rad) * l_tmp;
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t.anomaly = anomaly;
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t.anomaly_rad = t.anomaly * math.pi/180.0;
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t.delta_lon = 0.0;
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t.update_time = 0.1;
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t.running_flag = 0;
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return t;
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},
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set_anomaly: func (anomaly) {
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t.anomaly = anomaly;
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t.anomaly_rad = t.anomaly * math.pi/180.0;
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},
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set_delta_lon: func (dl) {
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t.delta_lon = dl;
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},
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list: func {
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print("Radius: ", me.radius, " period: ", me.period);
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print("L_vector: ", me.l_vec[0], " ", me.l_vec[1], " ", me.l_vec[2]);
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print("L_norm: ", math.sqrt(me.l_vec[0] * me.l_vec[0] + me.l_vec[1] * me.l_vec[1] + me.l_vec[2] * me.l_vec[2]));
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var pos = me.get_inertial_pos();
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print("Inertial: ", pos[0], " ", pos[1], " ", pos[2]);
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print("Rad: ", math.sqrt(pos[0] * pos[0] + pos[1] * pos[1] + pos[2] * pos[2]));
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var lla = me.get_latlonalt();
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print("Lat: ", lla[0], " lon: ", lla[1], " alt: ", lla[2]);
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},
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evolve: func {
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var dt = getprop("/sim/time/delta-sec");
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#var speedup = getprop("/sim/speed-up");
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#dt = dt * speedup;
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me.anomaly_rad = me.anomaly_rad + dt/me.period * 2.0 * math.pi;
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if (me.anomaly_rad > 2.0 * math.pi)
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{
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me.anomaly_rad = me.anomaly_rad - 2.0 * math.pi;
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}
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me.anomaly = me.anomaly_rad * 180.0/math.pi;
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me.delta_lon = me.delta_lon + dt * 0.00418333333333327;
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},
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get_inertial_pos: func {
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# movement around equatorial orbit
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var x = me.radius * math.cos(me.anomaly_rad);
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var y = me.radius * math.sin(me.anomaly_rad);
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var z = 0;
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# tilt with inclination
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z = y * math.sin(me.inc_rad);
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y = y * math.cos(me.inc_rad);
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# rotate with node longitude
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var xp = x * math.cos(me.nl_rad) - y * math.sin(me.nl_rad);
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var yp = x * math.sin(me.nl_rad) + y * math.cos(me.nl_rad);
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return [xp, yp, z];
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},
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get_future_inertial_pos: func (time) {
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var anomaly_rad = me.anomaly_rad + time/me.period * 2.0 * math.pi;
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while (anomaly_rad > 2.0 * math.pi)
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{
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anomaly_rad = anomaly_rad - 2.0 * math.pi;
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}
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# movement around equatorial orbit
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var x = me.radius * math.cos(anomaly_rad);
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var y = me.radius * math.sin(anomaly_rad);
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var z = 0;
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# tilt with inclination
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z = y * math.sin(me.inc_rad);
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y = y * math.cos(me.inc_rad);
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# rotate with node longitude
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var xp = x * math.cos(me.nl_rad) - y * math.sin(me.nl_rad);
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var yp = x * math.sin(me.nl_rad) + y * math.cos(me.nl_rad);
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return [xp, yp, z];
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},
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get_latlonalt: func {
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var coordinates = geo.Coord.new();
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var inertial_pos = me.get_inertial_pos();
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coordinates.set_xyz(inertial_pos[0], inertial_pos[1], inertial_pos[2]);
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coordinates.set_lon(coordinates.lon() - me.delta_lon);
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return [coordinates.lat(), coordinates.lon(), coordinates.alt()];
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},
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start: func {
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if (me.running_flag == 1) {return;}
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me.running_flag = 1;
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me.run();
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},
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stop: func {
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me.running_flag = 0;
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},
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run: func {
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me.evolve (me.update_time);
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if (me.running_flag == 1)
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{settimer(func me.run(), 0);}
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},
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};
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